A typical traction elevator system includes a car and a counterweight connected by multiple ropes, with the ropes extending over a traction sheave. The traction sheave is rotationally driven by a machine. The machine is mounted in a machineroom located above the hoistway, i.e., at the top of the building. The machineroom also houses other elevator peripheral equipment, such as the governor, the controller, and the drive for the machine.
Eliminating the machineroom provides potential savings in the construction of the building. In linear induction motor (LIM) elevators, the machine is a linear motor in which the primary and secondary are disposed in the hoistway. In one configuration, the primary is integral to the counterweight and the secondary is a column that extends through the hoistway. In other configurations, the primary is integral to the car frame. In either configuration, the machine is disposed in the hoistway, and thereby the machineroom may be eliminated.
Another elevator system configuration that eliminates the machineroom uses a disc type motor. This motor is smaller in axial direction and, as a result, may be positioned in the hoistway. An example of such a configuration is shown in European Patent Application EP 0 688 735. This patent application discloses a disc type motor disposed adjacent to the travel path of the elevator car and mounted on either the car guide rails or the counterweight guide rails. According to the specification, the guide rails provide a convenient support for the machine. A drawback to this mounting method is that the guide rails are designed and machined to provide a guiding mechanism for the car and counterweight. Using them as a support for the machine may increase the manufacturing cost significantly. In addition, the location of the machine is constrained by the need to place the guide rails in specific locations.
The above art notwithstanding, scientists and engineers under the direction of Applicants' Assignee are working to develop improved methods and apparatus to mount traction machines.